• 제목/요약/키워드: erosion equation

검색결과 211건 처리시간 0.029초

포신 마모 예측의 정확도 향상을 위한 실험적 방법 유도 (Derivation of Empirical Method to Enhance the Accuracy of Cannon Tube Erosion Rate)

  • 정동윤;오명호
    • 한국군사과학기술학회지
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    • 제5권3호
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    • pp.23-32
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    • 2002
  • We predict the erosion rate of unknown cannon tubes by substituting measured values of the standard cannon, 155㎜ Howitzer M185 and ballistic data for the erosion equation. We know ten measured erosion values of the standard cannon at every 400 rounds. An approximate formula is derived to interpolate six values up to 2,000 rounds. Numerical example is presented and its results are analyzed. The new erosion equation is also suggested. This equation produces more accurate cannon tube erosion rate than the Rauf Imam's empirical approaches. Computer simulations are presented.

Remote Sensing Information Models for Sediment and Soil

  • Ma, Ainai
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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    • pp.739-744
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    • 2002
  • Recently we have discovered that sediments should be separated from lithosphere, and soil should be separated from biosphere, both sediment and soil will be mixed sediments-soil-sphere (Seso-sphere), which is using particulate mechanics to be solved. Erosion and sediment both are moving by particulate matter with water or wind. But ancient sediments will be erosion same to soil. Nowadays, real soil has already reduced much more. Many places have only remained sediments that have ploughed artificial farming layer. Thus it means sediments-soil-sphere. This paper discusses sediments-soil-sphere erosion modeling. In fact sediments-soil-sphere erosion is including water erosion, wind erosion, melt-water erosion, gravitational water erosion, and mixed erosion. We have established geographical remote sensing information modeling (RSIM) for different erosion that was using remote sensing digital images with geographical ground truth water stations and meteorological observatories data by remote sensing digital images processing and geographical information system (GIS). All of those RSIM will be a geographical multidimensional gray non-linear equation using mathematics equation (non-dimension analysis) and mathematics statistics. The mixed erosion equation is more complex that is a geographical polynomial gray non-linear equation that must use time-space fuzzy condition equations to be solved. RSIM is digital image modeling that has separated physical factors and geographical parameters. There are a lot of geographical analogous criterions that are non-dimensional factor groups. The geographical RSIM could be automatic to change them analogous criterions to be fixed difference scale maps. For example, if smaller scale maps (1:1000 000) that then will be one or two analogous criterions and if larger scale map (1:10 000) that then will be four or five analogous criterions. And the geographical parameters that are including coefficient and indexes will change too with images. The geographical RSIM has higher precision more than mathematics modeling even mathematical equation or mathematical statistics modeling.

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An overview of applicability of WEQ, RWEQ, and WEPS models for prediction of wind erosion in lands

  • Seo, Il Whan;Lim, Chul Soon;Yang, Jae Eui;Lee, Sang Pil;Lee, Dong Sung;Jung, Hyun Gyu;Lee, Kyo Suk;Chung, Doug Young
    • 농업과학연구
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    • 제47권2호
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    • pp.381-394
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    • 2020
  • Accelerated soil wind erosion still remains to date to cause severe economic and environmental impacts. Revised and updated models to quantitatively evaluate wind induced soil erosion have been made for specific factors in the wind erosion equation (WEQ) framework. Because of increasing quantities of accumulated data, the WEQ, the revised wind erosion equation (RWEQ), the wind erosion prediction system (WEPS), and other soil wind erosion models have been established. These soil wind erosion models provide essential knowledge about where and when wind erosion occurs although naturally, they are less accurate than the field-scale. The WEQ was a good empirical model for comparing the effects of various management practices on potential erosion before the RWEQ and the WEPS showed more realistic estimates of erosion using easily measured local soil and climatic variables as inputs. The significant relationship between the observed and predicted transport capacity and soil loss makes the RWEQ a suitable tool for a large scale prediction of the wind erosion potential. WEPS developed to replace the empirical WEQ can calculate soil loss on a daily basis, provide capability to handle nonuniform areas, and obtain predictions for specific areas of interest. However, the challenge of precisely estimating wind erosion at a specific regional scale still remains to date.

New Empirical Approach to Enhance The Accuracy of Cannon Tube Erosion Rate

  • Chung, Dong-Yoon;Oh, Myoung-Ho
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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    • pp.231-232
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    • 2002
  • Various methods that utilize erosion rate measurement of standard cannon, 155mm Howitzer M185, as reference, are being used to calculate erosion rate of an interested unknown cannon tubes. We know ten measured erosion values of the standard cannon from 391 rounds to 4.000. An approximate function fitting these value s is derived. The new erosion equation is also suggested and computer simulations arc presented.

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40 mm 장축공동실린더의 마모경험식 유도 (Derivation of Empirical Erosion Equation of the 40 mm Long Hollow Cylinder)

  • 정동윤;오명호;신내호
    • Tribology and Lubricants
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    • 제25권3호
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    • pp.171-175
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    • 2009
  • One of the critical issues associated with the 40mm long hollow cylinder's development and maintenance is the prediction of cylinder erosion. The actual firing test is the most accurate method to measure the cylinder erosion rate. But it costs a great deal and requires a long measurement time. Hence many empirical methods have been proposed to predict the erosion rate and life span of long hollow cylinders. An EFC formula is calculated. An approximate erosion formula for the ammunition type A is derived to interpolate 16 observation values up to 4,000 rounds. A new erosion equation and muzzle velocity formula are also suggested. Several numerical results are presented.

토양의 침식과 보존에 관한 이론적 분석 3. 사면 토양의 침식에 관한 이론 (The Theoretical Analyses of the Soil Erosion and Conservation 3. Analytical Theory of Slope Erosion)

  • 장남기
    • 아시안잔디학회지
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    • 제10권1호
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    • pp.41-47
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    • 1996
  • The theory of slope erosion is developed along similar lines to the theory of heat flow in solid added to the correcting factor. if slope erosion in the forest and grassland proceeds according to the hypothesis, it is $\delta$y $\delta^2$y = k $\delta^2$y $\delta$$X^2$+f(s b. t) where 5 is internal properties of slope soil and b is biota on slope. When the variables of the equation of slope erosion are x = -λ the initial elevation=-f(λ), x=λ, x==a, the steady value of the initial elevation=y, and dy dx x=0> =O(t>o), respectively, the houndary condition due to the solution of the equation of slope erosion is y= 2 √$\pi$kt [∫a o λe $(X-λ)^2$4kt dλ- ∫ao- $(x+λ)^2$4kt dλ] + ∫∫∫ f (s.b. t)dtdbds

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태풍 루사에 의한 토양 침식량 산정을 위한 GIS와 범용토양손실공식(USLE) 연계 (Integration of GIS with USLE in Assessment of Soil Erosion due to Typoon Rusa)

  • 함창학;김병식
    • 대한공간정보학회지
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    • 제15권3호
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    • pp.77-85
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    • 2007
  • 토양침식의 산정은 많은 비용과 시간을 요구한다. 한 지역에서 토양침식을 예측하기 위한 많은 모형들이 있지만, 범용토양손실공식(USLE, Universal Soil Loss Equation)이 연 토양 침식량 산정을 위한 경험식으로 가장 널리 사용되고 있다. 토양침식은 강우강도, 토양의 종류, 토지 피복과 토지이용, 사면경사와 경사길이, 그리고 토양보전을 위한 시설의 영향을 받는다. 이러한 모든 변수들은 공간적으로 분포되어 있기 때문에 지형정보시스템(GIS)이 토양침식 영향평가에 널리 적용될 수 있다. 본 연구에서는 IHP 대표 유역인 보청천 유역을 대상으로 지형정보시스템(GIS)과 범용토양손실 공식을 연계하여 태풍 루사의 강우에 의한 유역에서의 토양 침식량을 산정하였다.

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유압시스템의 입자 침해 침식의 실험적 고찰 (An Experimental Investigation of Particle Impingement Erosion in Hydraulic Systems)

  • 이재천;김성훈
    • 한국자동차공학회논문집
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    • 제10권2호
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    • pp.117-122
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    • 2002
  • This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop complete analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

유압시스템의 입자 침해 침식의 실험적 고찰 (An Experimental Investigation of Particle Impingement Erosion in Hydraulic System)

  • 이재천
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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    • pp.15-21
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    • 2001
  • This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop an analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

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포신 마모 예측의 정확도 향상을 위한 적합 근사식 유도(I) (Derivation of Fitting Approximate Formula to Enhance the Accuracy of Cannon Tube Erosion Rate)

  • 정동윤;오명호
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2002년도 제35회 춘계학술대회
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    • pp.80-87
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    • 2002
  • We predict the unknown cannon tube erosion rate by using observed values of the standard cannon, 155mm Howitzer Ml85. We know the standard cannon's ten erosion observation values each 400 rounds. An approximate formula fitting the erosion values of the standard cannon has been derived. Numerical simulation applying this formula to the Rauf Imam's erosion equations is presented.

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